Medical Errors

IN the Harvard Medical Practice Study of 30,195 hospital records, diagnostic errors accounted for 17% of adverse events.

Leape et al, The nature of adverse events in hospitalized patients. N E J Med. 1991;324:377-384

Follow up study of 15,000 records from Colorado and Utah reported that diagnostic errors contributed to 6.9% of the adverse events.

Thomas et al, Incidence and types of adverse events and negligent care in Utah and Colorado, Med Care. 2000;38:261-271

Using same methodology, the Canadian Adverse Events Study found that 10.5% of adverse events were related to diagnostic procedures.

Baker et al, The Canadian Adverse Events Study: the incidence of adverse events among hospital patients in Canada CMAJ. 2004;170:1678-1686

The Quality in Australian health care study identified 2,351 adverse events related to hospitalizations, of which 20% represented delays in diagnosis or treatment and 15.8% reflected failure to “synthesize/decide/act” information.

Wilson et al, An analysis of the causes of adverse events from the Quality in Australian Health Care Study. Med J Aust. 1999;170:411-415

A study in New Zealand examined 6,579 inpatient medical records from admissions in 1998 and found that diagnostic errors accounted for 8% of adverse events; 11.4% of these were judged to be preventable.

Davis et al, Adverse effects in New Zealand public hospitals. N Z Med J. 2003;116:U624


Of 805 voluntary reports of medical errors from 324 Australian physicians, there were 275 diagnostic errors (34%) submitted over a 20 month period.

Compared with medication and treatment errors, diagnostic errors were judged to have caused the most harm, and were least preventable.

Bhasale et al, Analysing potential harm in Australian general practice. Med J Aust. 1998:169:73-76

Mandatory error-reporting system that rely on self-reporting yield fewer error reports than found using other methods. An example, only 9 diagnostic errors were reported out of almost 1 million ambulatory visits over a 5.5 year period in a large health care system.

Fischer et al, Adverse events in primary care identified from a risk-management database. J Fam Pract. 1997;45:40-46

Diagnostic errors are the most common adverse event reported by medical trainees.

Wu AW et al. Do house officers learn from their misgtakes? JAMA. 1991:265;2089-2094